The thing with Brad's system, and small ball in general-- is that your SF is just another shooting guard. Like Evan Turner, or Smart when he's on the floor with Thomas.
Also, you are leaving PJ3 off your list, a guy Ainge went out and got specifically for his ability to cover 4 positions on defense. Between he, Crowder and Jerebko -- we've got some decent options.
A few things:
- Playing a shooting guard at SF doesn't mean that guy can actually defend forwards, or switch onto big men.
- I continue to be mystified that people think PJ3 is going to be on the roster this year, let alone a part of the rotation. PJ3 is a "swing," anyway. So is Jerebko.
- I like Jerebko, but I hope he doesn't spend much time at the 3. Doesn't play to his strengths at all.
Brad Stevens uses four classifications for players: guard, wing, swing, big. The rotation right now projects to have four, maybe five guards, one wing, four or five bigs, and maybe one swing if Brad extends the rotation.